Re: [PATCH 2/2] x86/speculation: Provide application property based STIBP protection

[Jiri Kosina]

On Tue, 2 Oct 2018, Jon Masters wrote:

> > This patch provides an application property based spectre_v2
> > protection with STIBP against attack from another app from
> > a sibling hyper-thread.  For security sensitive non-dumpable
> > app, STIBP will be turned on before switching to it for Intel
> > processors vulnerable to spectre_v2.
> 
> A general comment. I think in practice this will be similar to the
> speculative store buffer bypass (aka "variant 4") issue in terms of
> opt-in mitigation. Many users won't want to take the performance hit of
> having STIBP by default for peer threads. We should make sure that we
> don't force users into a mitigation but retain an option. Whether it's
> default-on or not can be debated, though I think the vendors lean toward
> having default-off with an opt-in, and customers will probably agree. So
> anyway, I encourage a pragmatic approach similar to that for SSBD.

Which is what Tim's patchset is implementing on top.

Thanks,

-- 
Jiri Kosina
SUSE Labs